AB0776 Clinical and laboratory peculiarities of treatment-refractory ankylosing spondylitis.
Authors: K. Sakharova, S. Erdes, M. Cherkasova
Journal: Annals of the Rheumatic Diseases (2022)

Background Despite the availability of newest guidelines for the treatment of ankylosing spondylitis and various groups of genetically engineered biological drugs, there are still patients with refractory, i.e., resistant to therapy (with two or more genetically engineered drugs), AS, maintaining high clinical and laboratory activity. Objectives To analyze the clinical peculiarities of patients with refractory AS and to identify markers for early detection of such cases. Methods Patients who received 2 or more GEBDs and demonstrated a primary or secondary failure were considered cases of refractory ankylosing spondylitis. Twenty-four (16 %) patients with refractory AS (mNYC 1984) were enrolled, including 14 males, 10 females. This group was selected from 150 successive AS patients admitted to the clinic of the Scientific Research Institute of Rheumatology in 2020–2021. Ninety-three per cent of patients had HLA B 27, the mean age was 39 [31.5;49] years, the age of onset of the disease was 21.7 [15.5;29] years, the duration of the disease was 17.3 [11;24]. They were treated with drugs of various groups (i-TNF-α, IL-17, 6 and Janus kinase inhibitors). The refractory AS patients were compared to a control group with the corresponding gender, age of onset and duration of the disease admitted successively to the Institute during the same period. The examination followed the ASAS recommendations. All patients had additional nephelometric assay of SAA level using commercial reagent kits, reference value &lt; 5 mg\L. Results Median SAA, CRP, ESR levels, BASDAI, ASDAS scores and correlation indicators are shown in Table 1. Parameters Refractory AS Control р Median SAA, Me [25 th ; 75 th percentiles] 53.6 [15.75;205.5] 10.7 [4.9;31.1] p = 0.001 CRP, Me [25 th ; 75 th percentiles] 16.35 [3.55;63.1] 11 [4.9;29.3] p = 0.001 ESR, Me [25 th ; 75 th percentiles] 35 [20.5;110] 29.1 [13.9;48.1] p = 0.001 BASDAI, Me [25 th ; 75 th percentiles] 5.95 [4.85;6.6] 5.2 [4.8;6.1] p = 0.126 ASDAS-CRP, Me [25 th ; 75 th percentiles] 3.8 [3.11;4.49] 2.8 [2.2;3.2] p = 0.020 Peripheral arthritis, % 87.5 79.2 Enthesitis, % 66.6 70 Coxitis, % 75 71.5 Knee and hip replacement, % 20.8 8.3 The onset of the disease - urogenital infection, % 54 8.3 - juvenile onset, % 30 30 Correlation SAA and CRP r = 0.82 r = 0.55 p &lt; 0.001 andp &lt; 0.001 SAA and ESR r = 0.8 r = 0.5 p &lt; 0.001 andp &lt; 0.001 SAA and BASDAI r = 0.2 r = 0.3 p = 0.330 andp = 0.421 SAA and ASDAS r = 0.3 r = 0.4 p = 0.006 andp &lt; 0.001 CRP and ESR r = 0.8 r = 0.56 p &lt; 0.001 andp &lt; 0.001 CRP and ASDAS r = 0.3 r = 0.4 p = 0.295 andp &lt; 0.125 The refractory AS group had a higher SAA level compared to that of the control group (53.6 and 10.7, p = 0.001). There was no significant difference in the SAA, CRP levels, BASDAI and ASDAS scores. There was a strong association between SAA level and CRP level, ESR; correlation with BASDAI and ASDAS was non-significant and moderate. The clinical presentation was dominated by peripheral arthritises 87.5% and coxitises 75%, followed by enthesopathies 66.6%. No significant differences from the control group were observed. At the onset of the disease, a urogenital infection was detected in 54% of patients with refractory AS. Conclusion Patients with refractory AS demonstrate higher levels of SAA in the clinical presentations. Patients with the onset of reactive arthritis prevail. A study of new markers, including genetic ones, is required to identify a refractory disease at an early stage. Disclosure of Interests None declared